x86/resctrl: Don't stop walking closids when a locksetup group is found

When a new control group is created __init_one_rdt_domain() walks all
the other closids to calculate the sets of used and unused bits.

If it discovers a pseudo_locksetup group, it breaks out of the loop.  This
means any later closid doesn't get its used bits added to used_b.  These
bits will then get set in unused_b, and added to the new control group's
configuration, even if they were marked as exclusive for a later closid.

When encountering a pseudo_locksetup group, we should continue. This is
because "a resource group enters 'pseudo-locked' mode after the schemata is
written while the resource group is in 'pseudo-locksetup' mode." When we
find a pseudo_locksetup group, its configuration is expected to be
overwritten, we can skip it.

Fixes: dfe9674b04ff6 ("x86/intel_rdt: Enable entering of pseudo-locksetup mode")
Signed-off-by: James Morse <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Acked-by: Reinette Chatre <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: H Peter Avin <[email protected]>
Cc: <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 333c177a2471e01161fdb1131ecb6007a3c2ce67..869cbef5da818a693fdc62d2244076ba6d5e7153 100644 (file)
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2542,7 +2542,12 @@ static int __init_one_rdt_domain(struct rdt_domain *d, struct rdt_resource *r,
                if (closid_allocated(i) && i != closid) {
                        mode = rdtgroup_mode_by_closid(i);
                        if (mode == RDT_MODE_PSEUDO_LOCKSETUP)
-                               break;
+                               /*
+                                * ctrl values for locksetup aren't relevant
+                                * until the schemata is written, and the mode
+                                * becomes RDT_MODE_PSEUDO_LOCKED.
+                                */
+                               continue;
                        /*
                         * If CDP is active include peer domain's
                         * usage to ensure there is no overlap